[2] Once thought to be fungi because of their filamentous growth form and nutritional habits, Achlya and other water molds are now known to belong to the Kingdom Chromalveolata.
Red realized early on there were fungi that differed in aspects of compatibility and attributed these to what he called incompatibility factors A and B, further differentiating α and β in each.
Much of Red’s work has spawned many research questions about sex in fungi addressed more recently using model organisms like Saccharomyces cerevisiae, Cryptococcus gattii, and Candida albicans.
Through the influence of Red's work, it is now understood that mating-type identity is determined by regions of the genome called mating type or MAT loci.
These loci contain protein-coding regions for G protein-coupled receptors that sense ligands with varying specificity and signal through Mitogen-activated protein kinase cascades, as well as peptide pheromones and transcription factors involved in mate sensation, selection and reproduction.
He was heavily influenced by his interactions as a Masters student working with mycologist John Crouch at the University of North Carolina at Chapel Hill.
His first brief professor appointment at Indiana University was interrupted by his call to the Manhattan Project at Oak Ridge National Laboratory in Tennessee where he pioneered studies on the effects of Beta rays on rats.